Gas porting device for shotguns



Nov. l9, 1948. R. M. CUTTS GAS, Pomme DEvIcEFoR soTGuNs i 5Sheets-*Sheet 1 Filed April 2o, 1945' R. M. cuTTS GAS PORTING DEVICE FORSHOTGUNS Nov. 9, 1948.

Filed April 20, 1945 s shets-sheez 2 I Cuffs Mentor Nov. 9, 1948. R. M.CUTTS 2,453,121

` @As Po'RTING DEVICE FOR sHoTeuNs Filed Ap'ril 2o, 1945 :s sheets-sheet5 Patented Nov. 9, 1948 UNITED STATES Patent oFFlcE Richard M. Cutts,The Plains, Va., assignor of onehalf to Dorothea Lane Cutts, rllhePlains, Va.

Application April 20, 1945, Serial No. 589,315

. 1 1 This invention relates to gas porting devices for ordnance, havingfor its object to produce a construction simple in parts, no more costlyto manufacture, and more efficient-in use, than those heretoforeproposed.

With `these and other Lobjects in view the invention resides in thenovel details of construction and combinations of parts as will bedisclosed` more fullyghereinafter and particularly pointed out in theclaims.

Referring to the accompanying drawings forming a part ofgthisspeciiication and in which like numerals designate like parts in all theviews,

Figfl is a longitudinal sectional view of a device made in accordancewith this invention;

Fig. 2 is a transverse sectional view of said devicefsaid view taken ason the line 2 2 of Fig. 1 and looking in the directionof the arrows;

Fig. 3 is a view similar to Fig. 2 but showing a modication ofconstruction;

. Fig. 4 is a view similar to Fig. 1 but showing a further modication ofconstruction;

AFig. `4a, is a fragmentary view in section of a modication of the gasporting arrangement shown in Fig. 4;

A Fig. 5 is a longitudinal sectional view of a modified form of theconstruction;

Figs. 6 and '7 are enlarged detail sectional views of modified forms `ofribs which may be employed in the device;

Fig. 8 -is a detail view in section of a modiiied form of choke tube;and

Figs.r9 to 13 inclusive are longitudinal sectional views of stillfurther modifications of the invention.

This invention constitutes an improvement of the device disclosed in U.S. Letters Patent No. 1,773,260 dated August 19, 1930, granted toRichard M. Cutts and which` is directed to a compensating device for themuzzle end of a shotgun. The disclosure in that patent relative thevibrations given to the gun barrel, upon ringthe gun, and establishingwhat are known as bend and swing errors resulting in bullet impacts onthe target whichareabove, below, or to one side of, the desired point ofimpact, such errors varying with the powder charge and other knownconditions, is equally true and applicable to the instant invention.Also true and applicable are the statements in that patent relative theaction of the leakage gas and its pressure in the interstices of theprojected shot column resulting in the lateral expansion of the gas insaid column and thereby imparting lateral velocities to the shot pelletsin saidwcolumn (expanding said column), and the 4 claims. (ci. 89.44)

2 action of the powder wads upon the projected shot column to pan-cakethe base of said co1- umn. repeat here the explanation of these actionswhich are 4set forth in detail in said patent, since the device of thepresent invention is so generally similar to that of said patent.

According to the present invention, there is provided a device equally,if not more, capable oi' reducing and/or correcting the undesirablefeatures above referred to. aspect of the invention, approximately sixinches or' the muzzle end of the gun barrel may be cut off and then thedevice is threaded on the short-l overall length and velocities asbefore without( destroying the balance of the gun. Hence, the shotcharge reaches the expansion chamber without distortion of the shotpellets, and the extremely high temperature gases of explosion arepermitted quick lateral exhaustion, with relation to the axis of thebore. through the ports of said chamber. The rear or powder` wads arepractically consumed and/or torn to pieces by the time they leave thedevice due to the effect thereon of the hot gas turbulence in saidchamber, and the leading or shot wad is given a rapid or increasedforward acceleration due to the pressure of the gas in `theshot columnwhile passing through the choke tube, which permits said shot wad after;

leaving the choke tube to move laterally of the axis of shot projectionand hence prevents said wad from fdrifting back into and disrupting theprojected shot column. In traversing the expan-g sioncharnber, the shotcolumn elongates slightly and in this condition, and without thepresence therein of the white hot leakage gas and friction heat, reachesand readily passes through the choke tube` without loss of velocity and`without the undue disturbance to the shot pellets which has heretoforeresulted in pellet damage and/or deformation.

The single expansion ychamber of said patent, according to thisinvention, is provided with in ternal annular` ribs spaced from eachother and disposed between the gas discharge openings whereby suchexpansion chamber is divided into a plurality ci' successive,independent, and unconnected chambers gradually and diminishingly'exhaustingthe total of the gases of explosion while, at the same time,reducing appreciably the forward travel of such gases in the device,thereby increasing the reduction of recoil of the gun.

During the short period of time the shot column Therefore, it isbelieved unnecessary toV According to oneA is traversing the expansionchamber of this device, the Vibrations are being reduced and havesubstantially no effect upon the shot, but the damage due chiefly to thegas effect has been done. This improved device receives the column ofshot, under the urge of expansion by the intei-nal gas pressure as wellas the vibration, but the internal diameter of the ribs and/or thechamber proper may be made such as to materially prevent such expansion,and may cause recompression and reaiignment of any laterally dispersedshot pellets to any degree desired.

More specically, and referring vto Fig. l the shoegun barrel, which isindicated by the numeral 3, has threaded engagement Vas at i with oneend of the cylindrical casing 5 defining the expansion chamber generallyidentified by the numeral 6, whereby said casing has rotatableadjustability, so that the exhaust ports, later to be described may bepositioned top and bottom. The other'end of said casing may be inthreaded engagement as at 'i with a removable choke tube 8 provided withany suitable means, such as an outwardly extending flange serving as astop against' the end of the casing 5 as well as a means bywhich thetube member t may be screwed to said casing. The device comprising thisinvention has primarily to do with the expansion chamber to the end thatvarious choking arrangements' andv forms may be employed or the gun maybe fired without the removable end member, while maintaining the desiredeffects of gas control and shot column pattern resulting from theconstruction of this device.

The tube member 3 may be axially bored to 'i provide a conical surfacelil extending from the extreme inner end A of said member to a point B,as well -as a second conical surface il joining saidv surface Ill andextending forwardly from the point B to a, point C, the slope of thesurface Il being different from the slope of the surface I'; and saidmember may be provided with a third internal surface I2 which may beconical, cylindricahor of other generated formation, according to thedesired shot pattern after the shot havefleft the device, said surfacel2 extending from-the point C to the outer or forward end D ofsaidmember. In Fig. l these slopes have been exaggerated so as to be readilyvisible or apparent. (Dnl'thel'oth'er'hand, the surfaces Wand il maybe-made 'other than conical, e. g. they may be curved or arcuate andmerge with each other and/or merge with the surface I2 as indicated inFig. 4 tothe end that a continuous substantially smooth and unbrokeninner surface may extend from the innermost end or point A of 'the tubemember 8 to the outermost end point D thereof.

The conical surface i0, or its equivalent area ofthe continuous innerarcuate surface of the tubemember t, creates between the points A and Ba compression chamber; the conical surface lil, or'its equivalent areaof the continuous inner arcuate surface of said tube member 8, createsbetween the points B and C a recompression chamber for the laterallydispersed shot pellets; andthe' surface or area l2 creates between thepoints C and D a control (choke or otherwise) for the shot pellets withregard to the pattern desired when said pellets leave the gun. Theinternaldiameter at the muzzle of a choke tube determines the degree ofchoke obtained, wherefo'retiie choke tubes are provided with differentmuzzle diameters and are made interchangeable in orderv to obtain a shotpattern of any desired degree.l `In any choke tube, the sizeand shape ofthe sloped or curved area B-C will be suflicient to coactively engagethe shot pellets without detrimental effects thereon, and to direct saidpellets fairly smoothly into the choke represented by the area C-D, inaccordance with the powder charge and size of shot used, all as broughtout in detailed explanation in said patent.

The shot,l on emerging from tne gun barrel 3 intoJ the` cylindricalcasing; 5',.tend Ito/expand laterally to a known extent"aShereinbeOrestated. The shot column then traverses the expansionchamber B and may enterthe compression chamber .fl- BY and thereafterthe recompression chamber B-C. The internal diameter of the large end ofthis recompression chamber is at all times greater than the bore of thegun barrel. In Fig. l of the patent the shot column was shown as greatlyexpanded when entering the choke tube, but such showing was fordemonstration only; in actual practice such is not the case andtherefore such showing is an exaggerationi. In practice: it isdeiinitelyproven that the shoticoliumn impingeson the surface area Il` atalpoint.l which is so far forward as to be substantially'at the point ofentrance to the choke slopelorfarea;a

i2, or practically at point C as'illustratedinLFig." 1 ofthis instantapplication. Thus, the slopesrli and ii, which are one continuoussmooth`curve= in actual manufacture, arel mainly effective' in:

checking and counteracting thev force ofthe for--` wardly moving gas,and thus counteractrecoil of the gun. By the time the shotcolumnen'ierges1 from. the choke at point D, the vibration'sihere'-inbefore rnentioned'have been so dampened. that the swing and bend'errors are negligible and the internal gas pressure'has beenreduced,-witl'i1the result that the shot pellets true tothe target. l

In Fig. l the shot wad l5 of theired load is shown well within thechokechamber C-D -and ahead of the shot column, the shot are shownsubstantially unexpan'ded within the compression chamber A-B, andtherecompression chamber B'-C is shown functioning to contract4 intoalignment and compacted position all of theeX-panded'f shot pellets inthe fore portion of theshot column. The usual wad i6, used to separatethe'shotfrom the powder charge in the shell, is sh'owny following theshot but, for purposes of illustration' only; it is shown in itsoriginal shape and sizeyas herer 1` inbefore stated; its form is greatlychanged while traversing the device and actually itileaves thechoke tubeat D` in a decidedly broken-up or fragmental-y condition; as has beenproved by' spark photographs. The internal diameters of the" chokechamber C-D are such that the-shot' wad l5 will forma substantiallymechanical seal or plugin said chamber. While not denitely 'known` justwhere the greatest damage is doneto' the' powder wad i6, yet it isbelieved truethat there is a definite mass of the Wad material whichlreaches and enters the choke chamber C-D, which mass' is of sufficientformation to closely contact the walls of said chamber and thus providean effective seal, so-that the following'gas, still' under relativelytremendous pressure, will.' strike thev sloped'o-r curved surfaces I()Aand lli' which, being tapered or curved forwardly' and inwardly, willcause eddyings of said" gas' into whirls creating myriad vortices whichconstitute'. in effect a gas seal substantially preventing forwardtravel of further gases into and through the choke tube.

Therefore, the gases are permitted tol escapev laterally fromtliisdevice through a Vplurality of'v will fly substantiallyI antena;`

, posing all. of these ports above the `horizontal center of theexpansion chamber 6, a combinative eiect'of overcoming recoil andpreventing climb of themuzzle is obtained. In some instances `it may bedesired vto balance such ports as indicated in Fig. l by forming awsubstantial duplication thereof, as indicated at I8, in the bottomchamber wall, all of saidports being substantially diametrii callyopposed to each other with reference to an axial `plane of said chamber,and disposed either in the t'op andbottom, or in the sides, of saidchamber, as desired. In other instances it may be desired to form suchports as circular holes I9 substantially equally spaced entirely aroundthe chamber wall as indicated in Figs. 3 and 5. still other instances itmay be desired to balance only some ofsuch ports Il (or IS) withsubstantiallyl diametrically opposed ports I8 (or I9), leaving animperforate section 2U (see Fig. 4) in the wall-of s'aidichamberopposite the unbalanced ports Il (o'r'IS), such imperforate wall sectiontheir inner surfaces 26 lie substantially in a cylindrical plane coaxialwith the barrel bore, as a result oflwhich the wads l5 and IB formsubstantial seals successively with such surfaces after leaving thebarrel.

Dueto thefact that said ribs are imperforate and relatively closelyspaced from each other, these successive seals tend to prevent forwardtravel of any appreciable quantity of the gases of combustion, and alsomaterially reduce through the exhaust ports the amount of gas pressurewhich otherwise would reach and become `active in the shot column assaid column passes said ribs. Hence, with such minimization or internalgas pressure within the shot column, there is a material reduction inthe tendency of the shot'pellets to lateral dispersion, and thisreduction is such that the inner cylindricalfsurr`aces`2 ofthe ribs willconstitute means for keeping such dispersed pellets from too great alateral deviation from the axis of flight; this takes into considerationthe close spacingof the ribs, the axial extent of their cylindricalsurfaces, and the speed of projection of the shot column.

On the side of safety, the rear surface 21 of each rib may be sloped orcurved forwardly and inwardly as will be observed from Figs.' l, 4 and'7,

being disposed in that portion of the chamber wall as `will effect thedesired lateral movement of the muzzlethrough counteractionof thepressure ofthe gases escaping through the unbalanced ports I'I. Theimperiorate wall section 2U may beat either end of the expansion chamberor at va position intermediate of said-ends, and of an extentaccordingto the amount of lateral movement desired.` This unbalanced relationshipbetween the total of the top porting and the total of the Kbottomporting may also be accomplished by making provision for more gas to bereleased through the top ports for example than through the bottomports, and one way of doing this is to make one'or more of the ports ofan area which isgreater than the areaof another port. This isillustrated in Fig. 4a wherein ports I'I and I8 are substantially equalin area and hence are in balanced opposition, but the top port 2l is of'column when it is ready to leave the expansion chamber to produce theundesirable lateral shot velocities after` leaving the device,and at thesame time relieve such an amount of the'pressure from behind the powderwads I6 that said wads will not catch up to and pan-cake the rear end ofthe shot column.

According to Figs. l, 2 and 3, the expansion chamber I is provided witha plurality of transversely disposed annular ribs 25 supported by theWall of the casing 5 and extending inwardly of said chamber, said ribsbeing relatively parallel to each other with a rib disposed between twolongitudinally adjacent ports I1, I8 or I9. Each rib has an internaldiameter or bore which may be equal to or greater than the diameter ofthe shot column at such rib, and all of the ribs are 4Substantiallysimilar in construction wherefore and/or may be merged smoothly into thecylindrical rib surface 2B, in order that said rear surface may receivethereagainst any materially laterally dispersed shot pellets, and toturn and direct such pellets inwardly toward the axis of the shot columnso as to pass all of the ribs along with the other pellets of saidcolumn. Thus, the

ribs serve to maintain the relatively compact formation of the shotcolumn, with concurrent control of the quantity and pressure of theforwardly moving gases, so as to give maximum ef-" feet to the forwarddrive o-r projection of said column. The ports successively exhaustportionsV of said gases during the travel of theshot column through thedevice, but the sizes andv shapes, and spacings of the ports in a devicemay be varied and the total area of all the ports will be kept withinproper and desired operatinglimits, to the end that there is sufficientexhaustion of the gases' through the ports to prevent the buildingup ofa back pressure in the barrel which might be detrimental upon the nextopening of the breech of the gun. Should any pellets become dispersed`after passing the last or most forward rib, the' rear portions oftheinner surface of. the desired` choke tube willvactthereon, ashereinbefore dis. closed with respect tothe surfaces l0 and II, to,return them tothe body of the shot column.

The construction shown in Fig. 5 is a modiiica-` tion wherein the casing5 dening the expansion chamber `6 is of a lesser internal diameter, andis provided with a choke tube 8 the inner rearmost surface of which maybe outwardly and rearwardly flared (conical or arcuate), or the innersurface of saidtube may comprise a, single conical slope as shown inFig. 8. In other wor-ds said choke tube, havinga lesser internaldiameter, may have a very much reduced compression and recompressionchamber area.

The ribs may Lhave such cross-sectional shapes.

sectional shape asvshown in`Figs. land '7j This is evidnt'because whenthe shot column clearsth'e' anta-1er muzzle offthev `gun barrel it has'af tendency to exipand laterally due to internal gasipressure; air

pressure or resistance ahead of the colummand because it is nolonger'connedby the .barrel wall. When the rear face of the rib is in aplane substantially at right'angles to thedirection of shot projection,as illustrated in Fig. 6, and when the ribdiameterapproaches that of thebarrel bore, itis evident that the outer pellets of the expanding. shotcolumn will impingeV on the rear face of the rib adjacent its innermostedge, with consequent damage to such pellets.

.f The cross-sectional shape of ribs shown in Figs...l and?, on theother hand, .provides a rear rib vfacewhich -will deflect the outermostand dispersed pellets back to the shot column Without inicting anyserious damage .to saidoutermost pellets, the rear faces of all-the ribsthus performing.

the function of recompressing thev shot column, in successive steps, asthe column passes thev ribs or,y in other words, performingv thefunction of slopes Ill and H of said patent.

In the said patent itis evident that the choking oli and control of thegas takes place at only one pointv viz., in the rearward portion of thechoke tube, wherefore a certain amount of gas is bound to leak past therearmost (or powder) wad and thus enter the shot column. According tothe present invention, the series of ribs creates a plurality ofrelatively short subordinate expansion chambers in the main expansionchamber 6, to the end that a series of substantial gas seals are formedas the shot column and wa'ds pass theribs, and the gas, therefore, issuccessively valved off to the outside atmosphere through the ports beutween the ribs, thereby materially reducing the amount of gaswhichotherwise would enter the shot column before it enters the rearwardportion ofthe choke tube. Each rib is imperforate so that there is nogas communication between such adjacent subordinate chambers.

Coming now to the modifications of this invention illustrated in Figs. 9to 13 inclusive, it yis pointedout-that these constructions areexemplications of devices which might be more properly applicable torines or other ordnance capable primarily of discharging a single shotor bullet, as contradistinguished from the devices illustrated inFigs. 1to 8 and which have been hereinabove described as applicable to ashotgun where plural shot or shot pellets are discharged with one powdercharge. However, it is to be distinctly undersoood that thel principlesinvolved in all of the modifications herein illustrated, aresubstantially the same, particularly with respect to the treatment ofthe gases, and that. the speciicconstructions illustrated' as well asmodications or variations thereof are equally applicable to all. typesofordnance. Therefore, the constructions. shown inFigs. 9 to 13 are vtobe considered as improved modifications of those disclosed.. inU.l S.A

Letters Patent No. 1,605,393 granted November 2,v 1926, entitled Climbarrester, and No.. 1,636,357. granted'July 19, 1927, entitled Antilclimbdevice, bothissued to Richard M. Cutts, Jr.

In general, these modiiied constructions com prise a cylinder '5creating a main expansion chamber 6, said cylinder disposed. at themuzzle end of' the `gun barrelso that said expansion chamber receivesthe projectile and the gases of combustion as they leave the barrel. ThecylinderA is provided with transversely disposed annular ribs, ports forthe escape of the gases'of combustion,'and' a constricted forward" endor projectile Aopening having' suchY an internal diameter as to L8create a substantialvr gas.'y seali with the projectile when'. thevprojectile` is' passing' therethrough.. HncaingeneraLthe statementsgiven hereinbe.- fore with. respectr tothe constructions` shown; in'.Figs.. l to'. 8, .are applicable to the.. modifications. shown in Figs.94 to` 13; however, the, following; additionalY statements `will bemade. since. they.l arci deeme'dit'o berather'pertinent to saidlat`termodi-t cations. f

According.' toFig., 9. individual or. separatem:- terna'lfannularribssuch. as 4,.4.| and42 arepro.- Videdwithin the. cylinder 5, said.ribs. having ,thef cylindrical surfaces43., 44 and 45 respectively,but'. these surfaces. are. of diierent diameters,- the. rearmost ribv 4Bhaving the 1argest,1the foremost rib 42 havingthe smallest,.andv themiddle rib 4| having a diameter which is `intermediate the; others. Invotherwords-the diameters ofthesarib' surfaces successively decrease inthe-.directi'onofV` the path of the projectile (represented by thegar-Arow)4 through the. cylinders, withthe diameter of the foremost rib. justslightlyv greater than. the bore of the barrel so that when thevprojectileA passes-:through the foremost rib,v the projectile. and thecylindrical surface. -'of said rib WilltQg-f gethercreate a substantialgas seal.

Since all of the ribs are. of substantially the. same, thickness wherethey .loin the wall of the cylinder, and since each rib has atleast oneside. surface orv face such as llfwhich is:oblique. to theaxis of thecylinder, it willbe seen that thewidths ofthe cylindrical surfaces 43,44 and 45v are dif. ferent, decreasingv also in the direction of thepath. oi the projectile. Preferably it is the, rearface such as 6G of.each. rib which is made oblique. (though the front face may be similarlyformed), the Obliquity being conical or of other formation but inyanyevent pitched or directed forwardly and inwardly of the cylinder,whereby the for-v wardlyfmoving gases are not completely checkedI bysuch rear face. but are permitted easement into the chamber space aheadof the rib. However, at the foremost rib 42 the projectile createsa.substantial gas seal with the rib surface 45 when the projectile ispassingthrough said. rib, and consequently practically all.. forwardfmovement of" gas is stopped'here,A

The forward end o-f this device 'has its inner wall surface 41 forwardlyand` inwardly directed. to terminate in the projectile opening 48 justslightly greater than the. diameter of the pron jectile to also create asubstantial gas. seal` when. the projectile is passing therethrough. Arela! tively large port 49 isprovided in thev upper wall. portion of thecylinder'5 between the foremost. rib 42 and the projectile opening 48,and-a similar` port 5lis provided to the rear of and adjacent therearmost rib 40. Between each two ribs therevis provided a port oismaller areain'the upper wall of the cylinder as indicated at 5l, and

' the bottom Wall portion of the cylinder is imperforate.

AccordingY to Fig. l0 there is a somewhat similar construction, thechief difference being in the fact that two similar large rear po-rts.55 .are provided instead of the single rear port 50 shown` inFig. 9, inorder to permit the escape of a larger quantity of gas and so reduce theamount of gas to be val'veddown by the intermediate. ports 5|.

AccordingY toFig. 11 the single. rear. large. port 5U'i`s providedadjacent the rearmost rib 40, but a relatively small forward port 6U isprovided in they placeof` the. largevforward port 49. shown. in Figs.9`an'd' 10. Al1so,`the're are. but twvorribs pro,

.9 vided in this construction Yand between them there is provided asinglelarge port 6l of substantially the samearea as the rear port 50.Thus, 4the modifications shown in Figs. 10 land 11 are capable indifferent manners of eiecting the if:

release of substantially the same quantities of gas by the arrangementof port fvalving illustrated, clearly indicating the necessity ofrelatively Wide latitude in the protection of the principles of thisinvention.

The construction of Fig. 12 is similar tothat of Fig. 9 insofar as theribs andports are concerned, but the forward end of the cylinder isprovided witha cylindrical inner wall surface 55 instead of theforwardly and inwardly directed wall surface 4T shown in Fig. 9. Thediameter of the cylindrical Surface 65 is just slightly greater than thediameter of the projectile, and the length thereof is substantially fromthe forward port 49 to the end of the device, the purpose of thiscylindrical projectile tube or opening being to establish a'gas seal oflonger time duration, when the projectile is passing therethrough, thanwas the case with the construction. shown in Fig. 9.

In Fig. 13 there is illustrated a modification utilizing a singleannular rib flanked forwardly with a large upper port 49, and rearwardlywith a smaller upper port 5l, this arrangement particularly lendingitself to a condition of reduced powder charge, i. e., relatively `lowgas pressures, the larger port being providedifor positively valvingdown the pressure to an amount incapable of ,cocking the projectilewhile passing through the opening 48.

Therefore, from the constructions shown in Figs. 9 to 13 it will beseenthat the large rear port (or ports) such as 50 and/or 55 will valve`ofl or relieve the major gas pressure to 4prevent `the building-up ofundesirable pressure in the gun barrel. The large forward port (orports) such as 49 facilitate the release of gas not already exhausted bythe other ports and, since the projectile (or projectiles such as shotpellets if and a shot-gun)` tends to seal the muzzle of the device whenpassing throughthe projectile opening, the gas is thus morereadily-exhausted through a large port instead of going froward throughthe `muzzle `or projectile openingthereby resulting in increasedefficiency of the device. The number and size, as well as the locations,of the ports may be varied for different installations includingvariance of powder charge. The determining factor is in the principle ofvalving-off substantially all of the gas without a build-up of backpressure in the barrel. The intermediate ports, either large or small,may be provided at any and all points where peak pressures occur. 'Iheconstructions of Figs. 9 and l0 are well adapted to handle usualpressures generated by the propellant gas and projectile for normalinstallations. However, it is known that certain other installationswill require the release of the propellant gas at various points alongthe longitudinal extent of the device at the points where peak pressuresoccur. It is conceivable that there may be differences in ammunition forthe same cali-ber gun, i. e. there may be a difference in the powdercharge and the weight of the projectile, wherefore it is to beunderstood that this invention is flexible in order to cover generallysuch differences.

In low pressure guns a dead end expansion chamber, such as illustratedin Fig. 12, can be "1'0 used, and the gas is reacted out of the ports.However, in high pressure guns a dead-end alone would create such aterrific impact of forwardly moving gas that the Charpyblow would bematerially increased, resulting in a greater strain to the metal of thedevice, and the report would be more unpleasant to the rer. Therefore,it becomes highly necessary and essential to provide fractional andpositive valving ofthe gases by the ribs in conjunction with the ports.In gas porting devices for Shotguns, constructions similar to thoseshown in Figs. 9-to 13 may be utilized, but it is preferable in suchusage -to place the ports in both the top and bottom wall sections ofthe cylinder. i

It is to be understood that the number, shape, and spacing of the ribsfrom each other, `as well as the number, shape, spacing, and area of-theports associated with said ribs1 may be varied in order to so controlthe heavy gas pressure'as to prevent the said pressure frombuilding-back undesirably or hazardously into the barrel and/,or breechof the gun. Therefore, the constructions shown in the drawings are byway of example only.

What is claimed is:

1. In combination with a shotgun barrel through which shot as well aspowder and shot wads are projected by the gases of explosion `,of

a powder charge, a chamber mounted onA the muzzle of the barrel forreceiving the gases'j of explosion as well as the projected shot,V saidcharnber comprising a hollow cylindrical casing having its axisconcentric with the axis of the barrel, the inner diameter of saidcasing being greater than the bore of the barrel, said casingftherebyforming a chamber space toipermit expansion of the gases therein, thewall of said casing having longitudinally spaced apertures'toy releasef-.a portion of the expanded gases of explosion laterally of the casing,said wall also provided: with a plurality of separated substantiallysimilar annular, radially inwardly extending ribs providing a projectileopening in each rib, said ribs forming separate subdivisions of theexpansion.' chamber, at least one rib disposedbetween two'. of saidlongitudinally spaced wall apertures', and the projectile openingthrough each rib formedfof a diameter such as to provide a substantialgas seal with the projected powder and :shot wadsas the wads pass theribs, the rear face of each rib so sloped forwardly and inwardly to saidprojectile opening as to turn such stray shot, as may impingethereagainst, inwardly toward the axis of the shot column, Y

2. A device for attachment to the forward end of a shotgun barrel forporting the gases of explosion received from the barrel and forreceiving shot as well as powder and shot wads projected through thebarrel by the gases of explosion of a powder charge, said devicecomprising a, hollow cylindrical member to be concentric with the axisof the barrel when attached thereto, the inner diameter of said memberbeing greater than the bo-re of the barrel, said member thereby forminga chamber space to permit expansion of the explosion gases receivedtherein, the member having wall portions so formed that when the memberis attached to the shotgun barrel the side wall portions of said memberwill be imperforate and the top and bottom wall portions thereof willeach have longitudinally spaced apertures for releasing a portion of theexpanded gases of explosion laterally of the member, said member alsoprovided with a plurality of separated annular,

fenenei nadiallyiinwartily extendlngiribs; each 'ribprovid- 'ingf;a,.'projectile fopening, said .ribs forming fseparateesubdiyisionsrolthe :expansion ychamber, at :.least'v one :rib vdisposed between. twooft-said longitudinallly spacetifwall apertures,.andfthe:proje'cfho'l'low generallycylindrica'l ymember "having Aan 5:,

internal fdiameter greater than the bore 'f the 'gunSybarre'lto therebyprovide a chamber -space to "permit fthe expansion of the explosion`fgases =recived therein, the memberhavingwallportions so formed thatwhen the member is attached lto -Y .the shotgun barrel the sideWallfportions'ofsaid lfmerriberwill'be imperforate'andthe top andbotltom wall portions thereof-will -eaclfiihave a -plureality-'ef:apertures ffor releasing abortion of the u"expanded A'gases ofyexplosion Ilaterally of said imeniber, ratleast two `of said aperturesbeingv 'clis- 'posed fon :opposite lsides y.of a 1longitudinal faxial@lane of Ysai-'cl 1 member :and being intercepted :by #a 'commontransverse f plane-at right fangles f to the 'axisfdf saidvmember, saidwallfa'lso Aprovidedinteiriorlyithereof withsanfannular, radiallyextending erbxformlng separate subdivisions of vthefexpansion'dirarnber,:said rib disposed .between .twofoffsaid :apertures and fthefzopening 'through said rib formed fof :a :diameter such Izas ftoprovide .a sub- .rstantial :seal with the .rproiected powder andasmtmadsaasfthewads Vpass fsaidtrib, .the Yrearface cof isaid :rib :sofsloped :forwardly :and inwardly :to theneroiec'tile opening as .to fturnzsuch -stray f shot, innay --irrrpinge drhere'against, inwardly4toward ithe axis yinf thefs'mtcolumn.

54. Q'Afdeviceforiattachment .to :the forward end fofafr'shotgunbarrelfor porting ,the gasesiofcexplofsion .deceived (from the barreland ffor `.receiving .sshohaswwell fas lpowder "and eshot wad/sprojected i2 through the barrel by f the' ygases of explosion -of-ia-fpowder'chargevsaid device-comprising a hollow lgenerallycylindrical member to be concentric -withithe'faxisof Athebarrel'fwhenattached thereto, `the vinner '.iiameterfof said memberbeing-greater r`.than-theajourefof the barrel, said member therebyYforminga chamber space tcpermit expansion'of theexplosiongases receivedtherein, the member having'wall `portions so formed 'that when themember is attached to the shotgun barrel thezside wall portions fofA.said .member will be -imperfcrate end the top'andsbottom-wallportionsthereof will each have longitudinally spaced vapertures-for rel-easing ai portion of `the'expanded gases'of'ex- .pl-osionlaterallyy ofzt-he member, said 'memberialso ,provided 'with an annular,radially inwardly v.ex- .tendinggrib providing la projectile vopening,said Yrib forming-separatesubdivisions of .the'expansion .chamben',saidrib -`disposed between vtwo of Said longitudinally spaced'wallaperturesand the gproiectile openingkthrouggh said rib formed -ofa.diameter isuchsas to provide aisubstantiahgas seal with :the .projected`powder rand shot wads :as the fwads pass tt'herib. i

RICHARD M. CUT-115.

@REFERENCES fCITED The lfollowing vreferences are Aof record vin 'the leof vthis patent:

UNITEDST-ATES PATENTS vNumber lName y Date "785;'975 Mc'Clean `Ma,r.Y28, 1905 317,134 Smith Apr. :3, 1906 981,584 Miller Jari. '10, 1911:1,427,802 Goodwin sept. l'5,v 1922 A-1,T 9`8360 Pavek .'Aug. 31, 1926Lfll'l fSte'inegger i 'Nov.2,"1926 1;773260 lCutts 'Aug. 19,19301,801,258 '-BaT-ker A131121, 1931 1,939,700 "Hoifstettel Dec. 19,-'1933vv'2,'15615511557 'Cutts July'l-l, 1939 C22-,3131569 Raising 'Mar/9,'1943 "2322,370 Lance June 252, 1943 `2,34'8;1-I4 Dow -May 2, 11'94452153982298 :Finlay Apri-9,1946

FOREIGN PATENTS Number Country yDate v293;'553 :Germany -Feb. 15, y1917

